Study hopes to solve riddle of falling prawn numbers

A RESEARCH project looking at reasons behind declining school prawn numbers on the North Coast is under way in the Camden Haven Estuary, south of Port Macquarie.

It is thought declining catches could relate to poor water quality and the loss of habitat, a situation that is reported in other estuaries on the North Coast, especially the Richmond.

DPI senior research scientist Dr Matt Taylor said the project would determine whether school prawns were still recruiting to certain areas of the estuary and if water conditions were adversely affecting prawn growth and survival.

"We know from previous reports that the periodic presence of environmental conditions such as low dissolved oxygen, low pH and the occurrence of heavy metals can have deadly effects on prawns," Dr Taylor said.

"These conditions can occur in estuarine waters as a by-product of acid-sulphate soil oxidation.